PROJECT SUMMARY/ABSTRACT Inconsistent and incomplete mental health treatment is a significant barrier to symptom improvement and recovery for youth with psychiatric disorders. Continuity of mental health care, which involves regular appointments with consistent providers, is associated with treatment adherence, decreased hospitalization, lower costs, and improved health outcomes. In the absence of continuous outpatient treatment, youth are more likely to experience behavioral health crises and consequently may utilize emergency department (ED) services. However, the ED is often an inadequate setting for mental health assessment and treatment, and services provided are more costly and less intensive than outpatient care. Understanding whether continuity of outpatient mental health care is associated with the use of psychiatric emergency services may inform efforts to improve continuity of care; this may in turn reduce non-urgent youth psychiatric visits to the ED, which have been increasing over the last decade and pose a significant burden for hospitals. There is a critical need for research examining continuity of mental health care in youth. This project proposes to examine seasonal variations in mental health service use. Recent research suggests the importance of seasonal patterns related to youth psychiatric ED; identifying seasonal patterns in outpatient care may help explain these findings and indicate times of year when outreach and intervention may be needed. We also propose to address the lack of current research addressing racial and ethnic disparities in both psychiatric ED use and continuity of outpatient care. Given that minority youth with psychiatric diagnoses are less likely to access mental health services than their White peers, it is crucial that research consider differences in service use patterns between racial and ethnic groups. Understanding seasonal patterns in psychiatric ED and outpatient care is of particular importance for underserved minorities, who are already less likely to receive adequate treatment. The proposed study will examine patterns in ED and outpatient mental health care and investigate related sociodemographic disparities, including race/ethnicity and socioeconomic status. I will utilize health records (EHRs) collected from 2009-2016 at an urban community healthcare system that serves a multicultural population of over 140,000 patients. Aim 1 will replicate prior studies by using generalized linear modeling and path analysis to examine how youth psychiatric ED visits vary throughout the calendar year and over time. Aim 2 will extend previous research by examining how continuity of youth outpatient mental health care varies throughout the calendar year and over time. Aim 3 will address whether decreased continuity of outpatient mental health care is associated with increased utilization of psychiatric ED services. Within each aim, analyses will address sociodemographic differences.